Potbelly Stock, Despite Plunge, Not Yet a Buy

The sandwich chain's stock is down over 20% due to a reduced forecast. Bottom-fishers beware.

Potbelly's forecast is leaving a terrible taste in investors' mouths. Late Wednesday, the sandwich chain warned that second-quarter sales would miss expectations. It also lowered its full-year outlook.

Potbelly Corp. (ticker: PBPB) said it now expects to earn $83.6 million in revenue in the second quarter—compared to the $86.7 million consensus—as same-store sales decrease 1.6% (a 0.9% decrease after adjusting for holidays). For the...